SAN FRANCISCO (05/01/2000) - Digital phone lines offer convenient features, but they can be lethal to a modem without an analog converter. Konexx Corp.'s $129 Mobile-USB offers a small (4 inches), lightweight (3 ounces), but somewhat convoluted fix. For power, the Mobile-USB uses your laptop's USB port, instead of an AC adapter or batteries (as the previous version did). But the bundled USB cable is short, at just 3 inches. You also have to remove the telephone's handset from its cable, place the cable in the Mobile-USB, and then connect the PC modem to the other end of the device. Confused? I was, even though I had an illustrated map. But once everything was set up, my analog modem worked on a previously verboten digital phone. Konexx; 800/275-6354; www.konexx.com.